We've setup a process to manually sign our code using the SIGNTOOL from Microsoft. We generate our installation package using NSIS and it's time to start automating the code signing process as well as part of the NSIS scripts.
We do not use windows SDK for development so would prefer not making that a requirement for our developers. We have some people on Mac and Linux as well; anyone can make an installer and the installer maker is what will, hopefully, be signing the code automatically. We are using PFX files to sign the code.
So basically I'm trying to figure out, "how can I sign code without installing anything, except maybe one tiny file, so that it works on all three major OSes". Automating with NSIS is handled, but doing it without Windows SDK from any OS is not.